Apparatus and process to treat waste water for pollution control and industrial reuse

ABSTRACT

Apparatus and process for removing colloidal, oxygen demanding and odor causing organic materials, inorganic materials and other pollutants from waste water is provided. The initial pH and resistivity of the water is measured and adjusted to predetermined values. The color of the water is then measured and organic and inorganic materials are caused to precipitate from the water which is then subjected to a predetermined density of electrical current. The electrolysis coalesces colloidal materials which are removed mechanically and causes additional material precipitation, as well as acting to kill bacteria, viruses and other organic matter. Additional inorganic matter precipitation is induced and the water has a final pH, color and resistivity adjustment. An oxidizing agent is added to further reduce oxygen demanding and odor causing organic material and act on bacteria and other organic matter remaining. The water is then reusable or may be discharged into streams or sewer facilities.

United States Patent Armstrong 51 May 23, 1972 [54] APPARATUS ANDPROCESS TO TREAT WASTE WATER FOR POLLUTION Inventor:

Pollution Engineering International, Inc., Houston, Tex.

July 22, 1970 Assignee:

[56-] References Cited UNITED STATES PATENTS Mitchell ..210/96 Filippinoeet a1. ...210/96 X Mehl ..210/44 3355,019 11/9967 Mitchell..210/104 Primary Examiner-Michael Rogers Attorney-Thomas B. Van Poole,Francis A. Keegan, S. Ellwood Wilson and Peter N. Lalos [57] ABSTRACTApparatus and process for removing colloidal, oxygen demanding and odorcausing organic materials, inorganic materials and other pollutants fromwaste water is provided. The initial pl-l'and resistivity of the wateris measured and adjusted to predetennined values. The color of the wateris then measured and organic and inorganic materials are caused toprecipitate from the water which is then subjected to a predetermineddensity of electrical current. The electrolysis coalesces colloidalmaterials which are removed mechanically and causes additional materialprecipitation, as well as acting to kill bacteria, viruses and otherorganic matter Additional inorganic matter precipitation is induced andthe water has a final pH, color and resistivity adjustment. An oxidizingagent is added to further reduce oxygen demanding and odor causingorganic material and act on bacteria and other organic matter remaining.The water is then reusable or may be discharged into streams or sewerfacilities.

58 Claims, 13 Drawing Figures 60 PRELIMINARY TROD H/[Fwc TREATME MIXINGTANK ASSY SETTL/NG TANK TANK a; r. TANK PH AND FINAL OX/DA'NT POL ISH/NGADJUSTMENT POND 7Z1NK 1D/SCHARGE c DISPOSAL/52 1 MEANS f 125 r/ so 1 7a76 ELECTRODE FLOC SET/LING TANK ASSY TANK 2 2 1 1 1O Sheets-Sheet 3 \la. i'w

FIG. 3

Q D a 0 5 a r 0 7 m wh w Q a o a a 1 p 2 I l L. Brannon-ArmstrongINYENTOR Mid, WM? 17m ATTORNEYS Patented May 23, 1972 3,664,951

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RECYCLE I74 166 '75 PIPE r 'NPUT ix 760 PRELIMINARY 175 I TREATMENT FLOWTANK 3 METER 193 A L 792 MIX/N6 762 I877 I70 TANK CAUST/C IN Q 786- 72AC/D /N I- 785:) FROM FLOC 3 ACCUMULA T/ON TANK T TO AIR COMPRESSORDISPOSAL I 784 MEANS L. Brannon Armstrong F l G. 7 /NvENT0R FLOCDISPOSAL BY ATTORNEYS Patented May 23, 1972 l0 Sheets-Sheet .RNL QR.iirlll nmommwmmzoun L. Brannon Armstrong INVENTOR M, Wide & 0m

ATTORNEYS APPARATUS AND PROCESS TO TREAT WASTE WATER FOR POLLUTIONCONTROL AND INDUSTRIAL REUSE BACKGROUND OF THE INVENTION With the everincreasing problems of air and water pollution caused by our industrialtechnology, many industries are threatened by the tightening standardson air and water pollution. Particularly in the area of water pollution,many indus' tries foul waterways and sewage systems with rinse watersand other discharges containing high percentages of dissolved metals,organic materials, chemicals and particularly detergents and otherminerals that effect the quality and purity of the water. Suchindustries are the paper, steel, mining and various chemical industries.Though technology for treating such water discharge is available, it isextremely costly and few industries have been able to afford to installpollution treatment apparatus of the present technology, primarily basedon chemical means of treating polluted water. Because of the high costinvolved, few industries are willing to invest in such clean upapparatus and processes until they are forced to do so by federal and/orstate law.

Most of the present technology utilizes processes that are primarilychemical processes for attempting to cause precipitation of variousminerals and dissolved metals and removal of various materials whichcolor the water and give it noxious odors. Electrolysis is not new inthe sense that it has been used experimentally in pollution controlsystems, however, the cost of such systems has been prohibitive, becauseof the high voltages needed and the inefiiciency of the system.

The present invention remedies these problems of the prior art byproviding an electrolysis system for rendering water reusable or can beapproved for disposal in public sewage facilities, public streams andrivers.

SUMMARY OF THE INVENTION The instant invention provides a novel systemdesigned to process large volumes of industrial waste water that containcolloidal materials and other undesirable pollutants. Colloidalmaterials are finely disseminated materials in the water. They givecolor and odor to industrial waste water. Colloidal materials remainsuspended because of a small difference in specific gravity of theparticles in the surrounding water. These particles are uniformlyelectrically charged, and many colloids, including proteins, starches,celluloses, polypeptides and other substances possess negative charges.Other colloids are positively charged. These small particles can beremoved by electrically disturbing this charge by an electrolysisprocess and causing the particles to coalesce. The particles socoalesced frequently do not have an adequate specific gravity forprecipitation to the bottom of a tank in which the water is beingtreated, but they may be removed by foaming and mechanically removingthe foam from the water surface.

Electrodes used in this electrolysis process can be of many materials,but since one electrode will be gradually disintegrated during theelectrolysis process, the electrodes are put to work to perform otherduties. As electric current passes between the electrodes, the colloidalparticle sizes become,

larger and larger until they are sufficiently large to trap bubbles ofoxygen and hydrogen that are being evolved at the electrodes. Thesebubbles float the particles to the surface of the water as foam and thenmay be removed by mechanical means above mentioned. The foam from mostwaste water will be made up of organic material and can be burned ordried for recovery of valuable minerals or stored for disposal atapproved disposal areas.

Demineralization and demetalization of the industrial waste water can beaccomplished at the same time that the colloidal organic material isbeing removed via the process of foaming. Electric current that causesthe colloidal material to be removed will create ions of whatevermaterial of which the electrodes are composed, and these ions willgenerate a floc which can be utilized to precipitate various minerals,dissolved metals and other inorganic materials present in the water.

Since various metals and their ions will produce diflerent types of flocfor precipitating various types of minerals and inorganic matter, theelectrodes can be selected to do specific jobs. Aluminum and carbonelectrodes may be selected to remove temporary hardness, zinc electrodesmay be used to reduce water toxicity, kill viruses and reduce flocsettling time. Iron electrodes may be used if the water containssulfides.

In addition to removing the colloidal material and precipitating thedissolved minerals and inorganic material, bacteria, algae and otheroxygen-demanding matter may be destroyed by electrolysis. The oxygengenerated and bubbling through the water makes intimate contact withorganic material and will oxidize these organic materials as well asodorous gases of organic origin. Further, should the water have somechloride salts in it, these salts will break down and give off freechlorine gas which will also help kill bacteria and reduce odors.

The system utilizes flowmeters to measure the flow rate of the waterpassing through the apparatus for adjustment of the electrode apparatusand quantity of oxidant necessary to treat the water. The pH of thepolluted waste water is measured initially and is brought to a desiredlevel, generally in the range of 5.0 to 5.5, by treatment in apreliminary treatment tank involving the addition of either necessarycaustic or acid solutions to reach the desired pH level. Further, acertain quantity of seed" floc is introduced into the preliminarytreatment tank to initially precipitate a large quantity of organic andinorganic materials from the polluted water prior to treatment in theelectrode tanks in order to lighten the load carried by the electrodetanks performing the electrolysis process, thereby drastically cuttingthe power requirements for the electrolysis process. The resistivity ofthe water discharged from the preliminary treatment tank is measured andif the resistivity is too low, higher resistivity water from the systemin an advanced state of treatment is recycled back to a mixing tank toraise the resistivity of the water prior to being applied to the firstelectrode tank assembly.

In the electrode tank assembly, organic materials are coalesced andbubbled to the surface as foam, as hereinabove described, where they areremoved by the action of mechanical paddles which sweep the foam fromthe surface of the electrode tank and discharge it into a suitableconveying means for transportation to a preferred form of disposalmeans, such as a burner, in which the organic materials may be dried andreclaimed later if desired or burned completely leaving an inorganicresidue. Additional floc precipitation is induced in the first electrodetank, as hereinabove described, to reduce the quantity of inorganicmaterials and improve the color of the water. The water discharged fromthe electrode tank assembly is then delivered to a floc settling tank.

The water discharged from the first electrode tank assembly contains aquantity of floc and is used as a seeding floc in the first flocsettling tank, allowing the water to circulate through the flocprecipitate causing additional formation of floc and thereby removingadditional organic and inorganic materials from the water. The waterdischarge from the first floc settling tank is then applied as an inputto a second electrode tank assembly if one is necessary for furthertreatment of the water. In a second electrode tank assembly, a differentcombination of electrode materials may be utilized than was used in thefirst electrode tank assembly, in order to cause coalescing and foamingof additional organic materials and to cause additional flocprecipitation of other organic and inorganic materials not removed inthe first electrode tank assembly or the first floc settling tank.

As was hereinbefore described for the first electrode tank assembly, thematerials foamed to the surface of the second electrode tank are removedby a series of paddles that sweep the foam from the surface of theelectrode tank and deposit it in a suitable conveying means for transferto the desired disposal means. The output of the second electrode tankis discharged to a second floc settling tank along with a quantity ofseeding floc from the electrode tank, as was done in discharging treatedwater to the first floc settling tank. The second floc settling tankallows additional organic and inorganic materials to be precipitatedfrom the water thereby improving its color and completing thedemineralization and demetalizing process. However, there may be casesin which, because of the various and many combinations of minerals anddissolved metals and other materials in the polluted water, additionalelectrode tank assemblies and floc settling tanks may be necessary toaccomplish the process. However, it has been found that the combinationof two electrode tank assemblies and two floc settling tanks will handlesubstantially all industrial polluted waste water presently known.

The water discharged from the second floc settling tank may be useddirectly in most instances for reuse as process water, cooling water, oras boiler feedwater in industrial applications. However, if the water isto be discharged to a stream or river, it would be necessary to put thewater through a final pH an oxidation step in order to meet federaland/or state requirements. The Public Health Service requires a certainresidual chlorine be present in water prior to disposing of waste fluidsin public streams. This requirement is an attempt to kill any bacteria,reduce color and odors, and to reduce the oxygen demand of organicmatter still present in the disposed water.

To provide for such final pH and oxidant adjustment, the inventiondescribed herein further includes the use of a pH and oxidant adjustmenttank for receiving the water discharged from the final floc settlingtank. The pH, resistivity and color of the water discharged from finalfloc settling tank are all measured, and these measurements are utilizedto either add a caustic or acid solution from appropriate sources toadjust the pH to a final predetermined level. The required quantity ofoxidant for oxidizing the water in the tank for the purposeshereinbefore mentioned is also added. The water discharge from the pHand oxidant adjustment tank is discharged into a final polishing pond,merely a storage tank, in which the water is allowed to stand for ashort period of time for allowing the oxidation material introduced inthe oxidant adjustment tank to further act on the water in an attempt tokill additional bacteria, reduce odors and to reduce the oxygen demandof remaining organic material. The water discharged from the finalpolishing pond may then be reused in the industrial system, ordischarged into public sewage systems, streams, lakes or rivers.

The system as described herein utilizes an oxidant generator assemblyemploying a chlorine generator for supplying chlorine as the oxidationmaterial for use in the oxidant adjustment tank as well as a convenientmeans for producing the caustic and acid solutions for use in the pHadjustment of the water at various stages in the system.

The floc precipitate in the electrode tank assemblies and floc settlingtanks will continue to build up in the bottom of the tanks and wouldeventually fill each of the tanks unless discharged. Accordingly, flocheight sensors are utilized for monitoring the height of the flocprecipitate in each tank, and when it has reached a predetermined level,a solenoid valve is actuated allowing a portion of the floc precipitateto be discharged from each of the tanks to a central floc accumulationtank for use as seeding floc in the preliminary treatment tank ashereinbefore described. The excess floc accumulation in the preliminarytreatment tank and the floc accumulation tank, is discharged directly tothe desired disposal means as waste material.

Accordingly, the instant invention provides a novel water pollutioncontrol system utilizing an electrolysis process for advantageouslytreating large volumes of waste water that contain colloidal organicmaterials and other undesirable inorganic materials and pollutants.

Another feature of the present invention is to provide electrolysisapparatus for treating colloidal organic materials and generating a flocprecipitate of various minerals and inorganic materials from the water,adjusting the pH of the water and its color and introducing an oxidantfor killing bacteria and viruses and reducing the oxygen demand oforganic material remaining in the treated water.

Yet another feature of the present invention is to provide apparatus anda process for performing an electrolytic treatment of polluted wastewaters that will provide an inexpensive solution to the processing oflarge volumes of industrial waste water from many and varied industrialsources.

Still another feature of the present invention is to provide apparatusand process for preliminarily treating the polluted water andprecipitating a large amount of mineral, organic and inorganic materialsfrom the water prior to passing the water through the electrolysisprocess, thereby lessening the load on the electrolysis apparatus andsignificantly lowering the electrical power requirements.

BRIEF DESCRIPTION OF THE DRAWINGS In order that the manner in which theabove-recited advantages and features of the invention are attained, aswell as had by reference to the specific embodiments thereof which areillustrated in the appended drawings, which drawings form a part of thisspecification. It is to be noted, however, that the appended drawingsillustrate only particular embodiments of the invention and thereforeare not to be considered limiting of its scope for the invention mayadmit to further equally effective embodiments.

In the drawings FIG. 1 is a detailed mechanical schematic of the waterpollution control system according to the invention disclosed.

FIG. 2 is a perspective view of an electrode tank assembly as utilizedin the water pollution control system shown in FIG. 1.

FIG. 3 is a plan view ofan electrode tank assembly with the foam paddleassembly removed to show the arrangement of the electrodes in the tank.

FIG. 4 is a partial detailed vertical cross-sectional view of anelectrode tank assembly showing the foaming and floc precipitationaction resulting from electrolysis of the water under treatment, and theaction of the paddle assembly in removing foam from the electrode tank.

FIG. 5 is a detailed vertical cross-sectional view of a floc settlingtank shown in FIG. 1.

FIG. 6 is a detailed mechanical schematic of one embodiment of theoxidant generator assembly shown in FIG. 1.

FIG. 7 is a partial fragmentary detailed view of an embodiment of apreliminary treatment tank assembly having a paddle assembly and a meansfor aerating the waste water in the preliminary treatment tank.

FIG. 8 is an enlarged fragmentary detailed view of the T- head pipeassembly for introducing the waste water into the preliminary treatmenttank.

FIG. 9 is a detailed block diagram of the electrical control circuit ofthe water pollution control system shown in FIG. 1.

FIG. 10 is a detailed schematic diagram of the first control circuitshown in FIG. 9.

FIG. 11 is a detailed schematic diagram of the second control circuitshown in FIG. 9.

FIG. 12 is a detailed schematic circuit shown in FIG. 9.

FIG. 13 is a detailed schematic view of the fourth control circuit shownin FIG. 9.

diagram of the third control DETAILED DESCRIPTION OF THE PREFERREDEMBODIMENTS Referring now to FIGS. 1 and 9, the polluted waste water tobe treated enters the system as an input through pipe 20 and flow meter22 into the preliminary treatment tank 26. Just prior to entry into thepreliminary treatment tank, the pH of the polluted waste water ismeasured by a pH meter 24. Flow meter 22 may be any standard positivedisplacement or turbine-type flow meter generating an electrical signaloutput proportional to the flow rate and volumeof the water passingthrough pipe 20.

The pH meter is typically a glass electrode or half-cell in whichelectrical potential measurements are made through a glass membrane,indicating the pH of the solution. The electrical potential developed bythe glass electrode is transmitted via conductor 217 to the firstcontrol circuit 214 of the system control as shown in FIG. 9.

Simultaneously, the flow meter 22 is generating a series of electricalsignals proportional to the flow rate and volume of the water passingthrough pipe 20, and these signals are transmitted via conductor 229 tothe first control circuit 214. Once control circuit 214 receives signalsfrom flow meter 22, indicating that waste water flow is initiated, thecontrol circuit 214 will actuate either the acid pump 134 or the causticpump 136 to introduce either an acid or caustic solution from acid tank108 or caustic tank 106 via pipes 133 or 135, respectively, to tank 26.Depending upon the pH measured by meter 24, the caustic or acid solutionadded to the preliminary treatment tank 26 adjusts the pH of theincoming polluted waste water to a predetermined desired level.

Seeding flee from the floc accumulation tank 110 is pumped via pump 116and pipe 1 14 into the preliminary treatment tank 26 for mixing with theincoming polluted waste water and the acid or caustic solution beingadded. As the polluted waste water enters and travels through thepreliminary treatment tank 26 to the mixing tank 28, grit, sand andother heavy materials will settle to the bottom of the tank. The seedingfloc introduced will cause precipitation of some dissolved minerals andorganic material in the polluted water, removing some color from thepolluted waste water.

The level of the precipitated materials is measured by a floc heightsensor 30 in the preliminary treatment tank 26. A floc height sensortypically utilizes a closely spaced light source 45A and a photocell 45Bdisposed inside the tank at the desired level of the floc bed. Thephotocell 458 generates an electrical signal proportional to the lightreceived after the light beam from the light source 45A has passedthrough the water and accumulated floc bed. The electrical signalgenerated is transmitted via conductor 219 (see FIG. 9) to the firstcontrol circuit 214. When sensor 30 has sensed the predetermined levelof the precipitated material in preliminary treatment tank 26, the firstcontrol circuit signals solenoid valve 122 via conductor 223, openingvalve 122 and allowing floc precipitate in the bottom of tank 26 to flowby gravity through pipe 118 to disposal means 52. Disposal means 52 isadvantageously a burner where the floc material is either dried forreclamation of various minerals and metals precipitated in the floc, orburned and reduced to carbon dioxide (CO water (H 0), and inorganic ashwhich is discharged for disposal or reclamation. Of course, otherdisposal means may be utilized. While the discharge of the flocprecipitate from the bottom of preliminary treatment tank 26 throughpipe 118 is accomplished by gravity as hereinabove described, it mayreadily be seen that depending on the layout of the system, pumps may beutilized to remove the floc precipitate from an appropriate tank to thedesired disposal means 52.

As the preliminarily treated water leaves the treatment tank 26, itenters mixing tank 28 where the resistivity of the water is measured byresistivity meter 32. Resistivity meter 32 may be any conventionalliquid resistivity measuring means. As shown in FIG. 9, the electricalsignal output of the resistivity meter 32 is applied via conductor 246to the second control circuit 216. If the resistivity of the water inmixing tank 28 is below the desired level prior to treatment in thefirst electrode tank assembly 40, the second control circuit willactuate pump 68 via conductor 245 and recycle a portion of the affluentdischarge in pipe 60 from the first floc settling tank 56 to be returnedthrough pipe 66 into mixing tank 28. Since the water discharged via pipe60 from the first floc settling tank 56 has had organic and inorganicmaterial removed as will be hereinafter described, it has a much higherresistivity than the water preliminarily treated in tank 26, andaddition of this recycled water will dilute the waste water in mixingtank 28 and increase its resistivity.

The output of mixing tank 28 is discharged via pipe 34 through a secondflow meter 36 and introduced into first electrode tank assembly 40through a manifold 35 and vertically spaced inlet pipes 31, 33 and 37for vertically injecting the water over the entire height of theelectrodes for uniform distribution. Depending on the size of electrodetank 40, manifold 35 may have more or less injection pipes into theelectrode tank as needed.

Flow meter 36 may be identical to the flow meter 22 previouslydescribed, and its electrical signal output is applied via conductors249 and 248 to the second electrical control circuit as shown in FIG. 9.In addition, the color of the water is sensed by color meter 38 prior toits input into the first electrode tank assembly 40. Color meter 38 is aconventional color meter utilizing a closely spaced light source andphotocell pickup, the electrical signal output generated by thephotocell varying directly in response to the color of the water, or theamount of light that is able to pass through the finely suspendedcolloidal materials in the water. This generated electrical signal istransmitted to the second control circuit 216 via conductor 247.

Depending on the volume, flow rate and color of the water, the secondcontrol circuit 216 will regulate the electrical power requirementneeded by the electrodes in the first electrode tank assembly 40.Further, if the color of the water ex ceeds predetermined limits, pump116 is actuated via signals from control circuit 216 through conductor243, to pump additional seeding floc from the floc accumulation tankthrough pipe 114 to the preliminary treatment tank 26. The additionalseeding floc is used to precipitate additional minerals, organic andinorganic materials from the water until the color meter reads anacceptable color level.

The water entering electrode tank assembly 40 through pipe 34 passesthrough a labyrinth of vertically oriented electrodes, spaced from 4;inch to 2 inches apart as required to treat the water, and made up ofvarying materials or combinations of materials as required for treatingthe specific polluted waste water. In electrode tank assembly 40, thecolloidal material suspended in the water is electrically treated by thepassage of direct current between the electrodes for reorienting theparticle polarity and causing the colloidal particles to coalesce andfloat to the surface as foam as will be hereinafter more particularlydescribed in detail. This foam is then removed from the electrode tankassembly by a foam paddle assembly 46. The foam removed by the paddleassembly 46 is deposited onto a ramp 48 where the foam slides by gravityonto a conveying means 50 which transports the foam to a disposal means52 hereinabove described.

At the same time that the colloidal organic material is being removed bythe process of foaming, demineralization of the waste water is beingaccomplished by floc generated by the specific electrode material beingutilized. The floc so generated is formed and traps dissolved mineralsand metals not removed in the preliminary treatment tank 26. Some ofthis floc precipitate settles to the bottom of the electrode tank 42,the level of which is monitored by a floc height sensor 44. Floc heightsensor 44 is identical to the floc height sensor 30 utilized in thepreliminary treatment tank 26 hereinabove described. The electricalsignal output of floc height sensor 44 is transmitted via conductor 250to the second control circuit 216 as shown in FIG. 9, and solenoid valve124 is actuated via a signal transmitted through conductor 252 foropening valve 124 and allowing excess floc precipitate to drain throughpipe 121 into the floc accumulation tank 110. Of course, if the flocaccumulation tank is not advantageously located for suitable removal ofthe floc precipitate from electrode tank 42 by gravity, a pump may beutilized as hereinbefore described in connection with tank 26.

The treated water from electrode tank assembly 40 is discharged viavertically spaced pipes 430, 431 and 432 into a manifold 61 and throughpipe 54 for introduction into the first floc settling tank 56. As willbe hereinafter more particularly described, it is critical that somefloc precipitate is transferred with the treated water through pipe 54into the floc settling tank 56 where it acts as a seed floc in tank 56for promoting additional floc growth and precipitation. To control thequantity of floc precipitate transferred from electrode tank 40 to thesettling tank 56, each of the discharge pipes 430, 431 and 432 haverespective valves 435, 436 and 437. By opening or closing the valves inany combination, the quantity of floc precipitate transferred with thewater discharged from electrode tank 40 may be controlled as desired.

As the floc generated in floc settling tank 56 coalesces into larger andheavier particles, their weight then causes faster settling of the flocto the bottom of the tank. The level of floc is sensed by the flocheight sensor 58 for maintaining a constant floc bed height in thebottom of tank 56. The floc height sensor 58 is, of course, identical tothe floc height sensors 44 and 30 hereinabove described. The electricalsignal output from floc height sensor 58 is transmitted via conductor251 to the second control circuit which in turn actuates solenoid valve126 with an electrical signal transmitted via conductor 253, openingvalve 126 and allowing excess floc from tank 56 to be discharged throughpipes 127 and 123 to the floc accumulation tank 1 in the same manner aspreviously described for electrode tank assembly 40.

The output of floc settling tank 56 is discharged into pipe 60 as aninput to a second electrode tank assembly 70. As the treated water fromfloc settling tank 56 is discharged through pipe 60, color andresistivity are measured by color and resistivity meters, 62 and 64,respectively. The electrical signals of the color meter 62 aretransmitted via conductor 270 to the third control circuit 218, whilethe electrical output of resistivity meter 64 is applied via conductor271 to the control circuit 218 for regulating the electrical powerrequirements needed by electrodes in the second electrode tank assembly70. Color meter 62 and the resistivity meter 64 are identical to thecolor meter 38 and resistivity meter 32 hereinabove described.

Electrode tank assembly 70 may have its electrodes spaced equal to orcloser than the spacing of the electrodes in the first electrode tankassembly 40. In addition, the electrode materials in electrode tankassembly 70 may be difierent than the electrodes in electrode tankassembly 40, depending on the quality of the polluted waste water undertreatment, and the type of materials desired to be removed from thewater.

Additional oxidation of the waste water will occur in electrode tankassembly 70, as well as removal of additional organic and inorganicmaterial as described above for electrode tank assembly 40. The heightof the floc precipitate in electrode tank 72 is measured by floc heightsensor 74, identical to the floc height sensors hereinbefore described.The electrical signal output of floc height sensor 74 is applied viaconductor 272 to the third control circuit 218 which actuates solenoidvalve 128 via conductor 274, opening the valve and allowing excess flocprecipitate to be discharged from electrode tank 72 through pipes 125and 123 to the floc accumulation tank 1 10.

The water entering the second electrode tank assembly 70 passes througha labyrinth of electrodes as hereinabove described for the firstelectrode tank assembly 40, where the colloidal materials suspended inthe water are electrically charged by the passage of direct currentbetween the electrodes to coalesce the colloidal particles and causethem to be floated to the surface as foam as will be hereinafter moreparticularly described. This foam is then removed by paddle assembly 76and deposited on the ramp 78 where it slides onto a conveying means 80for transportation to disposal means 52, hereinbefore described.

The treated water from electrode tank 72 is discharged through pipe 82to the second floc settling tank 84, where additional floc precipitationoccurs as above described for the first floc settling tank 56. Flocheight sensor 86 maintains a constant height of floc precipitate in flocsettling tank 84 by applying an electrical signal via conductor 273 tothe third control circuit 218 which in turn actuates solenoid valve 130via an electrical signal through conductor 275. Valve 130 opens, andexcess floc precipitate is discharged through pipe 129 into the flocaccumulation tank 110, as hereinbefore described for electrode tanks 42and 72, and floc settling tank 56.

The system shown in FIG. 1 utilizes a combination of two electrode andfloc settling tanks to accomplish its treatment of the waste pollutedwater, Of course, depending on the degree of pollution of the water andthe types of colloidal organic materials, dissolved minerals and otherinorganic materials present in the water to be treated, additionalelectrode and floc settling tanks may be added in the system asrequired. Of course, in some simple applications only a single electrodetank assembly and a single floc settling tank may be necessary.

The treated water output of floc settling tank 84 is discharged throughpipe 88 to a pH and oxidant adjustment tank 96. The color, resistivity,and pH of the water flowing through pipe 88 are measured by meters 90,92 and 94, respectively. The color meter 90, the resistivity meter 92and the pH meter 94 are identical to the meters hereinabove describedfor accomplishing the same measurements. The electrical output of colormeter 90 is applied via conductor 294 to the fourth control circuit 220;the electrical control signal from the resistivity meter 92 is appliedvia conductor 295 to control circuit 220; and the electrical signalfromthe pH meter 94 is applied via conductor 296 to control circuit 220. Asmay be seen in FIG. 13, the control signals from flow meter 36, colormeter 90 and resistivity meter 92 are applied to motor 282 forcontrolling variable transformer 281 for controlling the electricalpower requirement of the oxidant generator assembly 104 (see FIG. 9).Control circuit 220 also operates pumps 117 and 139 via conductors 297and 298, respectively, distributing either a caustic solution from tank106 through pipes 161 and 137 or an acid solution from tank 108 throughpipes and 131 to the pH and oxidant adjustment tank 97 for the final pHadjustment phase of the system.

The fourth control circuit 220 also energizes motor 282 for controllinga variable transformer 281. 220 volt AC electrical power is supplied viaconductors 209, 211, 288 and 289, switch 280, and conductors 283 and 285to the oxidant generator assembly 104 for generating the necessaryoxidant supply for oxidizing the water in tank 96. The quantity ofoxidant needed is determined by demand, which is proportional to theelectrical power supplied to the oxidant generator assembly electrodesvia conductors 292 and 293 from DC rectifier 284. Power to rectifier 284is supplied from the secondary winding 287 of variable transformer 281via conductors 290 and 291. AC power to the primary winding 286 oftransformer 281 is supplied via conductors 209, 211, 288, 289 and switch280, respectively. Motor 282 varies the coupling between the primary andsecondary windings of transformer 281, thus varying the AC power appliedto the DC rectifier and varying the DC output to the oxidant generatorassembly electrodes for determining the quantity of oxidant generatedand available for oxidizing and treating the water in the pH and oxidantadjustment tank 96.

As shown in FIG. 1, the oxidant generator assembly is a chlorinegenerator assembly 104, utilized to generate byproduct of caustic andacid solutions for storage in tanks 106 and 108, respectively, as wellas chlorine gas as the oxidant, as will be hereinafter more particularlydescribed. Of course, the oxidant generator assembly may be either achlorine or ozone (O generator for providing oxidant to tank 96. If anozone (O generator is utilized, the caustic and acid solutions couldconveniently be supplied from separate bottles or tanks of the neededsolution.

The oxidant is delivered to tank 96 by means of water from the finalpolishing pond 100, which is pumped through pipe 141 by pump 142 to aconventional aspirator assembly 165, where the oxidant is dissolved inthe water and then transferred through pipe 143 to tank 96. The oxidantis delivered to aspirator 165 through pipe 157 and valve 158. The outputof the pH and oxidant adjustment tank 96 is discharged through pipe 98to the final polishing pond 100 where the oxidant continues to act onthe water and provide it with some residual oxidation. Treated waterfrom the final polishing pond is discharged through pipe 102 from pond100 for reuse or for disposal. If an ozone (O generator is utilized, thewater from pond 100 would be routed to the oxidant generator assembly104 where the oxidant would be dissolved in the water using an aspirator165 or a similar apparatus to dissolve the oxidant in the water andreturn to pH and oxidant adjustment tank 96.

As may be seen in FIG. 9, the electrical control circuit derives its ACpower input from a 220-volt source 208, controlled by master switch 210,and thence distributed via conductors 209 and 211 to the four controlcircuits. Of course, as hereinabove mentioned with regard to FIG. 1, ifadditional combinations of electrode tank assemblies and floc settlingtanks are necessary, additional control circuits will be necessary.Similarly, if only one electrode tank assembly and floc settling tankcombination is utilized, the third control circuit shown in FIG. 9 maybe eliminated.

Power to the first electrical control circuit 214 is provided viaconductors 209 and 211, switch 212, and conductors 213 and 215.Similarly, AC power to the second control circuit 216 is provided viaconductors 209, 211, 237 and 238, and switch 228. Power to the thirdcontrol circuit is provided via conductors 209, 211, switch 256 andconductors 255 and 257, while AC power to the fourth electrical controlcircuit 220 is provided via conductors 209, 211, 277 and 279, and switch278.

Referring now to FIGS. 2, 3 and 4, a perspective view, a plan view and apartial vertical cross-sectional view of a typical electrode tankassembly 40 is shown. In FIG. 2, the water from mixing tank 28 (seeFIG. 1) is applied through pipe 34 to a manifold 35 and thence into oneend of electrode tank 42 via pipes 31, 33 and 37 at various verticallevels. The electrodes 150 are vertically mounted and horizontallyspaced, each electrode alternately having one longitudinal end spacedfrom the wall 41 of tank 42 to provide a labyrinth through which thetreated water must pass prior to discharge into a discharge manifold 61and thence through pipe 54 into floc settling tank 56 (see FIG. 1). InFIG. 3, solenoid valve 124 is shown as is discharge pipe 121 fordischarging the floc precipitate from electrode tank 42 via pipe 121 tothe floc accumulation tank 110 (see FIG. 1). The floc height sensor 44is shown mounted in position on the wall 41 of electrode tank 42 havinga light source 45A and a photoelectric cell 458 which generates a signalin proportion to the light received after the light has passed throughthe floc bed, thereby closing the electrical circuit as hereinbeforedescribed. The electrode tank would most advantageously be constructedof heavy concrete sidewalls 41 (see FIG. 4) and have a number ofelectrodes 150 typically made of carbon, aluminum, iron, zinc, lead orcombinations of these as required for treating the water and creatingand generating the requisite mineralized floc precipitate. Of course,many other electrode materials may be utilized, depending on theminerals, colloidal particles and other pollutants in the water to betreated. To handle large volumes of waste water daily, as would becommon in many industries, large electrode tanks would be required,probably built as huge concrete tanks in the ground.

The electrode tank assembly 40 is shown having mounted thereon a foampaddle assembly 46 (see FIG. 2). The paddle assembly comprises aplurality of longitudinal paddle frames 146 having attached the lengthof one longitudinal edge a resilient paddle wiper 148. The ends ofpaddle frame 146 are attached to a pair of spaced apart chains 151 thatcarry the paddles longitudinally across the top of electrode tank 42,and maintain the paddle wiper 148 in direct contact with the upper edgeof electrodes 150. Paddle wiper 148 is made of an insulated materialsuch as rubber, polyurethane, polyethylene or similar materials whichwill not conduct electricity. Chains 151 are each driven by a pair ofsprockets 152, the sprockets for each respective chain being attached toopposite ends of a drive shaft 153 and an idler shaft 154. Also attachedto drive shaft 153 is a drive sprocket 155 which is driven via a chain156 by any conventional driving means, such as an electrical or gasolinemotor. The paddle assembly 46 is supported above the tank 42 by means ofa structural frame 43.

As shown in FIG. 4, the treated water 147 passing through the labyrinthof electrodes 150 within electrode tank 42 contains colloidal materialsuspended within the water because of the small difference in specificgravity of the particles and the surrounding water. These particles areuniformly electrically charged, and many colloidal materials, includingproteins, starches, celluloses, polypeptides and other substancespossess negative charges. Other colloids are positively charged. Thesecolloidal particles can be removed by electrically disturbing theircharge and causing them to coalesce. The manner of disturbing theelectrostatic stability of the colloidal particles is accomplished bythe process of electrolysis, i.e., passing a direct current betweenelectrode pairs through the water to be treated. The electrodes used forthis purpose can be of any of the materials previously described.

As electrical current passes between the electrodes, the particlescoalesce and the colloidal particle size becomes larger and larger untilthey are sufficiently large enough to trap bubbles of oxygen andhydrogen that are being evolved and released at the electrodes. Thesebubbles float the particles to the surface of the water as foam 149 (seeFIG. 4). The foam 149 rises and projects above the top surface of theadjacent electrode pairs 150. The moving paddles 146, having a flexiblewiper 148 in contact with the top surface of electrodes 150, sweep thefoam 149 from the top surface of the electrodes and across lip 49 andonto the ramp 48. The foam deposited on the downwardly slanting surfaceof ramp 48 slides by gravity onto the moving surface of conveying means50 for transporting the foam to disposal means 52 (see FIG. 1).Conveying means 50 may be any convenient conveyor or belt system, or achute downwardly slanting from the electrode tank 42 to the disposalmeans 52.

As hereinabove described, the foam from most waste water will be made upof organic material and can be burned or dried for recovery of valuableminerals and other usable byproducts stored for future disposal.

Demineralization and demetalization of the treated water can also beaccomplished at the same time that the colloidal organic material isbeing removed by the foaming action during the electrolysis of thewater. The electrolysis process that causes the colloidal material tocoalesce, generates floc material according to the specific electrodematerial being used and precipitates dissolved minerals and metals thatcan cause water hardness, and may also be used to produce ions to killbacteria, algae and the like. Electrode materials can be selected to dospecific jobs. Aluminum and carbon may be selected to remove temporaryhardness; zinc electrodes may be used to reduce water toxicity, killviruses and reduce the floc precipitate settling time. Iron electrodesmay be used if the water contains sulfides. The floc precipitate 145settles to the bottom of tank 42 and forms a floc bed which increases indepth until discharged as hereinabove described.

As mentioned above, bubbles of oxygen and hydrogen are being evolved atthe electrodes and are used to help generate the colloidal foam. Thebubble size and quantity can be controlled by adjusting the current usedin the electrolysis process. The oxygen will oxidize some of the organicmaterial present in the water to be treated. The oxygen and hydrogenbubbles are both beneficial, as hereinabove mentioned, in helping floatcoalesced material to the surface for removal. If there are chlorideions present in the water, free chlorine gas bubbles are generated, andthey also will oxidize some of the organic material as well as helpfloat coalesced material to the surface. If carbon is used for at leastsome of the electrodes, carbon dioxide gas bubbles are generated whichwill help control the pH as well as convert carbonates present in thewater to the more soluble bicarbonates.

The use of aluminum electrodes will produce aluminum ions, which in thehydroxide form are very beneficial in forming floc 145 and precipitatinghardness minerals. The use of some zinc or lead electrodes will giveadded weight to the aluminum floc particles and aid in a more rapidsettling of the floc precipitate. Zinc ions are a biocide used fordestroying bacteria and viruses as hereinbefore mentioned. The use ofiron electrodes provides a very inexpensive electrode material which isbeneficial in removing finely disseminated organic material from water.Different electrodes may be used to provide specific ions needed fortreatment of a combination of specific contaminants present in thepolluted waste water.

Referring now to FIGS. 1 and 9, the electrical power needed by electrodetank assemblies 40 and 70 is controlled by control circuits 216 and 218.The electrodes 150 of electrode tank assembly 40 receive a varying DCvoltage dependent upon the water flow rate and volume, the color asmeasured by flow meter 36 and color meter 38, the electrical signaloutputs of which are applied to circuit 216 via conductors 248 and 247,respectively. As will hereinafter be more fully explained, the secondcontrol circuit 216, in response to the signals from flow meter 36 andcolor meter 38, controls motor 222 via conductor 244 for operatingvariable transformer 226. AC power is applied to the primary winding 232via conductors 209, 211, 235 and 236 and switch 230. Motor 222mechanically varies the coupling between primary winding 232 and thesecondary winding 234 of transformer 226 to control the AC voltageapplied via conductors 239 and 240 to the DC rectifier 224. The variableoutput of rectifier 224 is applied to electrodes 150 of the firstelectrode tank assembly 40 via conductors 241 and 242 for accomplishingthe electrolysis process. The greater the flow of water and the darkerthe color of the water entering tank assembly 40, the greater will bethe DC voltage applied to the electrodes via conductors 241 and 242.

Similarly, control circuit 218 responds to the measurements of flow rateand volume by flow meter 36, color by color meter 62 and resistivity byresistivity meter 64, applied as signal inputs via conductors 248, 270and 271, respectively, and controls the operation of motor 258 and hencethe operation of variable transformer 260. The secondary winding 264 isconnected to the DC rectifier 267 by conductors 265 and 266. Thecoupling between the primary and secondary windings of transformer 260may be mechanically varied by operation of motor 258, thus varying theAC voltage induced in the secondary winding 264. The variable ACvoltage, applied to rectifier 267 produces a variable DC voltage forapplication to electrode tank assembly 70 via conductors 268 and 269, asconditions require more or less voltage to accomplish the electrolysisprocess.

Referring now to FIGS. 1, 5 and 8, the floc settling tank, similar tothe electrode tank 42, hereinbefore discussed, would advantageously beconstructed having concrete. walls 63 for handling large volumes ofwater typical of industrial application. As was hereinbefore mentioned,it is critical that some of the floc in the electrode tank 42 betransmitted through pipe 54 into the floc settling tank 56 as a seedingfloc. This is necessary in order that a continuous supply of floc beavailable in settling tank 56 for causing a continuous flocprecipitation 145 in the tank. Pipe 54 enters tank 56 at an inclinedangle and terminates in a T-shaped head 55, having a series of spacedholes 57 facing the back wall 63 of tank 56 (see FIGS. 5 and 8). Pipe 54is inclined at an angle so that the floc transmitted with the treatedwater from electrode tank 42 will gently slide down the inclined surfaceinside of pipe 54 and be circulated into the first chamber 109 of tank56 (see FIG. 5).

Tank 56 is separated into first and second chambers, 109 and 111,respectively, by means of a partition plate 53 disposed laterally acrosstank 56. It will be noted that plate 53 is not vertical but slantsslightly toward the first chamber 109 in order that any floc carried bythe treated water 147, as it rises in the first chamber and spills overthe top lip 105 of plate 53, will gently slide down the inclined surfaceof plate 53 into the space between plates 53 and 47. Plate 47 is avertical partition plate spaced longitudinally from plate 53 anddisposed laterally between the opposite sides of tank 56. However, plate47 does not touch the bottom of tank 56 and allows the treated water 147and floc precipitate 145 to pass under the bottom edge of plate 47 intothe larger area of the second chamber 111. Also disposed in chamber 109is a lateral plate 51 spaced behind separation plate 53 and is slantedat an angle, as shown in FIG. 5, to help circulate the water and flocprecipitate 145 flowing through holes 57 in the head 55 upwardly andthen downwardly and around the bottom edge of plate 51 and upwardly intothe space between plates 51 and 53.

The floc precipitate level in the first chamber 109 will rise toapproximately the level shown at 169, depending on the quantity and flowrate of water being treated. The floc precipitate level 171 betweenplates 47 and 53 will be slightly lower than the floc precipitate levelin the first chamber 109, since a smaller quantity of floc material isescaping over the top edge of plate 53. The floc level within the mainportion of the second chamber 111 of the floc settling tank 56 willbuild to a height approximately shown at 173 where the floc level willbe monitored by the floc height sensor 58, functioning identically tothe floc height sensor 44, hereinbefore described with respect toelectrode tank 42. When the floc precipitate reaches a predeterminedlevel, the floc height sensor 58 signals the second control circuit (seeFIG. 9) and solenoid valve 126 is in turn energized, thereby openingvalve 126 and allowing floc precipitate 145 to discharge from theinterior of the second chamber 111 through pipes 127 and 123 to the flocaccumulation tank 110 as hereinabove described.

The treated water 147 rises within the interior of settling tank 56until it spills over the upper edge of the laterally disposed weir 59 atthe end of the settling tank opposite input pipe 54. The water thatspills into weir 59 contains very little or no floc precipitate comparedto the water injected via pipe 54. The treated water in weir 59 isdischarged through pipe 60 to the input of another electrode tankassembly, if another electrode tank assembly is required, as hereinabovediscussed.

If an additional electrode tank assembly 70 and settling tank 84 areneeded, as illustrated in FIG. 1, and previously described, electrodetank assembly 70 and settling tank 84 would be constructed and functionidentically to electrode tank assembly 40 and settling tank 56,respectively. Of course, if additional electrode tanks or settling tanksare required, they would also function in the same manner as electrodetank assembly 40 and settling tank 56. As hereinbefore described in thedetailed discussion of electrode tank assembly 40, each successiveelectrode tank, if needed, may utilize a different combination ofelectrode materials, depending on the pollutants in the water and thenecessary action desired on organic and inorganic substances present.

As described above, the polluted waste water is first emptied into apreliminary treatment tank 26 (see FIG. 1) for initial pH adjustment andinitial floc seeding to precipitate a first quantity of mineralized andorganic material from the water. In addition to the above-mentionedpreliminary treatment, some polluted waters require a primary foamingtreatment. This foaming treatment may be provided for in a secondembodiment of the preliminary tank assembly 166, as shown in FIG. 7.Preliminary treatment tank 168 receives water input through a pipe and aflow meter 162. The flow meter 162 is identical to the flow metershereinabove described as used in the system shown in FIG. I. A pH meter164 determines the initial pH of the water for application ofappropriate caustic or acid solutions through pipes 187 or 186 asrequired. Seeding floc from a floc accumulation tank such as the tank110 shown in FIG. 1, will be applied directly to the preliminarytreatment tank 168 by means of a pipe 185. An air compressor 182introduces compressed air through tubing 188 to the bottom of tank 168through a porous block material 190 to break up the airstrearn into manytiny bubbles and create a bubble curtain 192, which assists in floatingmaterials to the surface where these materials, and any floating trash,are removed by paddle assembly 174.

The seeding floc injected through pipe 185 precipitates a certainquantity of mineral and organic materials from the water 193 to form afloc precipitate 145 shown in the bottom of tank 168. The level of thefloc precipitate will be monitored by means of a floc height sensor 170,whose operation is identical to the floc height sensors hereinbeforedescribed for use with the apparatus described in FIG. 1. When the flocprecipitate 145 reaches a predetermined level, floc height sensor 170would cause the first control circuit 214 to actuate solenoid valve 184for discharging some of the floc precipitate via pipe 183 to a disposalmeans (not shown) in the identical manner hereinabove described forpreliminary treatment tank 26. Similarly, the resistivity of the waterin mixing tank 172 would be monitored by resistivity meter 207,identical to resistivity meter 32 previously described, and would causethe recycling of water from the output of the first settling tank 56 viapipe 180 to the mixing tank for increasing the resistivity of the wateras liereinbefore explained. The output of mixing tank 172 is dischargedthrough pipe 178 to the input of the first electrode tank assembly 40 ashereinabove described for preliminary treatment tank 26 (see FIG. 1). InFIG. 9 it may be seen that air compressor 182 is actuated by means of anelectrical signal applied via conductor 221.

The paddle assembly 174 is identical to the paddle assembly hereinabovedescribed for the electrode tank assemblies 40 and 70 and sweeps anyfoam, floating materials and trash from the surface of the treated waterin the preliminary treatment tank 168 where it is deposited on the ramp175. The material slides down ramp 175 to a conveying means 176 fortransporting to a suitable disposal means, such as disposal means 52hereinabove described.

As hereinbefore described for the system shown in FIG. 1, a separateoxidant generator assembly 104 may be utilized for generating andapplying an oxidant to the pH and oxidant adjustment tank 96. Separatecaustic and acid tanks 106 and 108 may be utilized for supplying theappropriate caustic or acid solution in the various treatment tanks foradjusting the pH of the water at various stages. However, the oxidantgenerator assembly 104 may be a chlorine generator assembly as shown inFIG. 6, whereby caustic and acid solutions will be generated during thegeneration of the oxidant itself, thereby assuring a continuous supplyof oxidant and caustic and acid solutions. The oxidant generatorassembly 104, shown in FIG. 6, cmploys a sealed tank 203 separated by asemipermeable membrane 204 for forming two chambers. An electrode 201 isdisposed in one chamber and an electrode 202 is disposed in the otherchamber, separated by the semipermeable membrane. Electrodes 201 and 202receive DC potentials from DC rectifier 284 via conductors 292 and 293,respectively (see FIG. 9).

A positive electrical potential is applied to electrode 201, while anegative electrical potential is applied to electrode 202 of thechlorine generator. Brine from tank 194 is circulated through pipes 191and 189 by pump 196 into the chamber containing the electrode 201. Withthe potentials applied to the electrodes, a direct current passesbetween the electrodes through the brine solution, and chlorine gas isevolved at the positive electrode 201, bubbles up through the brinesolution and into pipe 200, passes through valve 198 and intodistribution pipe 140. Simultaneously, free hydrogen gas is beingevolved at the negative electrode 202, bubbles up through the solutionand into pipe 199 and thence into pipe 140. Sodium is also produced atthe negative electrode and immediately combines with water to formsodium hydroxide and is discharged through pipe 139 to caustic tank 106for use in adjusting the pH of the treated water. The chlorine gascontains some water vapor and when combined with the hydrogen gas formsa hydrochloric acid solution in acid tank 108, for use in pH adjustmentas hereinbefore described. In addition, free chlorine gas present inacid tank 108 passes through valve 157 and pipe 158 to be dissolved inwater pumped from the polishing pond through pipe 141 and 143 (seeFIG. 1) to the pH and oxidant adjustment tank 96. The chlorine mayeffectively be dissolved in the water by means of a conventionalaspirator 165.

Fresh water is supplied to oxidant generator assembly 104 through pipe159 (see FIGS. 1 and 6) for use in controlling the fluid levels of brinetank 194 and the chamber containing the negative electrode 202. Waterthrough pipe 159 passes through pipes 177 and 181 and valve 197 to brinetank 194, and through pipes 177 and 179 and valve 195 to the negativeelectrode compartment.

If ozone (O is required as an oxidant, it may be produced by utilizingan O generator using a high voltage alternating current impressed acrossopposing electrodes having air as an electrolyte. The O oxidant wouldthen be dissolved in the water from the polishing pond via pipes 141 and143 and aspirator 165, previously described, and distributed to the pHand oxidant adjustment tank 96.

The output of the acid tank 108, shown in FIG. 6, is applied throughvalve 132 and pipes and 133 by pump 134 to the preliminary treatmenttank, and through pipes 115 and 131 by means of pump 1 17 to the pH andoxidant adjustment tank 96 as hereinabove described. Similarly, theoutput of caustic tank 106 is applied through valve 113 and pipes 161and 135 by pump 136 to the preliminary treatment tank and through pipes161 and 137 by pump 138 to the pH oxidant adjustment tank 96 ashereinabove described.

Referring now to FIGS. 9 through 13, the electrical control circuit ofthe water pollution control system will be described in greater detail.A detailed schematic of the first control circuit 214 is shown in FIG.10. The 220-volt AC supply line voltage applied via conductors 209 and211 is applied via conductors 213 and 215 and switch 212 as an input tothe control circuit. The electrical signal output of flow meter 22 isapplied via conductor 229 as one input to amplifier 302. When switch 212is closed, AC power is applied via conductor 301 to amplifier 302, andif a flow meter signal is received via conductor 229, the amplifier 302generates an electrical voltage applied via conductor 310 to the relaycoil 309 for closing relay contacts 311. When relay contacts 311 areclosed, 220-volt AC power is applied to the remainder of control circuit214. The output of amplifier 302 is also applied via conductor 422 as aninput to a conventional integrating circuit 324.

Electrical power through the closed relay contacts 311 is applied viaconductors 312 and 303 to amplifier 304, via conductors 312, 316 and 305to amplifier 306, and via conductors 312, 316 and 307 to amplifier 308.The signal from the photocell of floc height sensor 30 is applied viaconductor 219 to amplifier 304 and then applied via conductor 313 torelay coil 314, normally energized with relay contacts 315 open. Whenthe electrical signal from photocell 45B of floc height sensor dropsbelow a predetermined value, indicating the maximum height of the flocbed, relay coil 314 is deenergized, thus closing relay contact 315. Theclosing of contacts 315 applies 220-volt AC power via conductors 312,418 and 223 to relay coil 419 of solenoid valve 122. Energization of therelay coil 419 operates valve 122a of solenoid valve 122 thus allowingthe excess floc precipitate from the preliminary treatment tank 26 (seeFIG. 1) to discharge through pipe 118 to the floc accumulation tank 110.

Similarly, an electrical signal from floc height sensor 112 of tank 10is applied via conductor 227 to amplifier 306 which in turn produces anelectrical voltage applied via conductor 319 to energize relay coil 320and maintain relay contacts 321 in a normally open condition. When theproper floc height in tank 110 is reached, the signal drops below apredetermined value, coil 320 is deenergized and relay contacts 321 areclosed. The closing of relay contacts 321 applies 220-volt AC power viaconductors 312, 316, 305, 317 and 225 to relay coil 420 of solenoidvalve 120. Energization of relay coil 420 operates valve a and allowsexcess floc precipitate in the floc accumulation tank 110 (see FIG. 1)to be discharged through pipe 1 19.

The pH meter, or glass electrode 24, disposed in pipe for reading the pHof the polluted waste water prior to its entry into the preliminarytreatment tank 26 (see FIG. 1) generates an electrical signal appliedvia conductor 217 to amplifier 308. The output of amplifier 308 isapplied via conductor 322 as input to a signal discriminator circuit323. The signal discriminator 323 is a conventional discriminatingcircuit for discriminating between signals above or below a given outputlevel from amplifier 308, denoting the pH level of the water. The outputof the discriminator is applied via conductor 325 to a conventionalintegrator circuit 324. Integration of signals from amplifiers 302 and308 by circuit 324 produces an output at either conductor 326 or 327,depending on whether the pH of the treated water needs an acid orcaustic solution added to adjust the pH to a more neutral level,commonly between 5.0 and 5.5. If additional acid must be added to thepreliminary treatment tank 26, a signal will be generated by integrator324 and applied via conductor 326 to the relay coil 328. With relay coil328 energized, relay contacts 330 are closed and electrical power isapplied via conductors 312, 316 and 233 to the acid pump 134. On theother hand, if caustic needs to be added to the water in the preliminarytreatment tank 26 (see FIG. 1) the integrator 324 will produce anelectrical signal applied via conductor 327 to relay coil 329. With coil329 energized, relay contacts 331 close, and electrical power is appliedvia conductors 312, 316, 318 and 231 to energize caustic pump 136. Withthe addition of the acid or caustic solution the pH of the waterchanges, thus varying the electrical signal applied via conductor 217from pH meter 24. When the pH has reached the desired level, theintegrator 324 output will reach a preset level, thus deenergizing coils328 or 329 and opening the closed contacts 330 or 331 to shut off theappropriate acid or caustic pump 134 or 136.

If an air compressor 182 is utilized as shown in the embodimentdescribed above in FIG. 7, electrical power to the air compressor willbe applied via conductors 312 and 221 immediately upon the energizationof relay coil 309 and the closing of relay contacts 311 when flow meter22 indicates the passage of water through pipe 20 (see FIG. 1). Itshould be noted that when water movement through flow meter 22 drops toa level such that no electrical signals are produced and applied viaconductor 229 to amplifier 302, relay coil 309 will be deenergized thusopening relay contacts 311 and disabling the remaining circuitry of thefirst control circuit.

Referring now to FIGS. 1, 9 and 11, 220-volt AC power is applied to thesecond control circuit via conductors 237 and 238, switch 228 andconductor 333 to amplifier 332. When flow meter 37, disposed in pipe 34between mixing tank 28 and the first electrode tank assembly 40 (seeFIG. 1), is actuated by the flow of water in pipe 34, electrical signalsare generated and applied via conductor 249 to amplifier 332. The signallevel output of amplifier 332 is applied via conductor 335 to the relaycoil 339, and via conductor 337 as one input to integrating circuit 342.Upon energization of relay coil 339, relay contacts 341 are closedthereby enabling the remainder of the circuitry of control circuit 216and applying 220-volt AC power via conductor 237, closed contacts 341,conductors 343 and 344 to amplifier 334, via conductors 343, 345 and 349to amplifier 336, via conductors 343, 345 and 354 to amplifier 338, andvia conductors 343 and 345 as an input to bridge and amplifier circuit340.

The floc height sensor 44 monitoring the height of the floc precipitatein the first electrode tank assembly 40 (see FIG. 1) generates anelectrical signal applied via conductor 250 to amplifier 334. The outputof amplifier 334 is applied via conductor 346 to relay coil 347, whichwhen energized maintains relay contacts 348 open. As previouslydescribed for floc height sensors and 112 (see FIG. 10), when the flocheight reaches the maximum limit, relay coil 347 is deenergized, closingcontacts 348. This action applies AC power via conductors 343, closedrelay contacts 348, and conductor 252 to relay coil 421 of solenoidvalve 124. When relay coil 421 is energized, valve 124a is actuated tothe open position, and allows floc precipitate in the bottom ofelectrode tank 42 to be discharged through pipe 121 to the flocaccumulating tank 1 10 as hereinabove described.

Similarly, the floc height sensor 58 of the first floc settling tank 56applies electrical signals via conductor 251 to amplifier 336. Theamplified output of 336 is applied via conductor 350 to relay coil 351,which when deenergized (when the predetermined fioc height is reached)closes relay contact 352 and applies AC power via conductors 343, 345,349, 353 and 253 to relay coil 423 of solenoid valve 126. Theenergization of relay coil 423 actuates valve 126a to the open positionand allows the discharge of accumulated floc precipitate in the bottomof floc settling tank 56 through pipe 127 as hereinabove described.

The electrical signal output of color meter 38 is applied via conductor247 to amplifier 338. The amplified output of amplifier 338 is appliedvia conductor 357 to relay coil 358 for closing relay contacts 359 andapplying electrical power via conductors 343, 345, 354, 356 and 243 topump 116 for pumping seeding floc from tank through pipe 114 to thepreliminary treatment tank 26 (see FIG. 1) as hereinabove described. Theoutput of amplifier 338 is also applied via conductor 355 as a secondinput to a conventional integrating circuit 342. The electrical signalgenerated by resistivity meter 32 is applied via conductor 246 to aconventional bridge and amplifier circuit 340. The bridge circuitutilizes a standard Wheatstone bridge circuit and conventionalamplifier. The output of bridge and amplifier circuit 340 is applied viaconductor 361 to coil 362 for closing relay contacts 363 and providingelectrical power via conductors 343, 345, 360 and 245 to pump 68 forrecycling treated water discharged at the output 60 of the first flocsettling tank 56 through pipe 66 back to the mixing tank 28 as shown inFIG. 1.

Integrating circuit 342 is a conventional integrating circuit forintegrating the amplified flow meter signal applied via conductor 337and the amplified color meter signal applied via conductor 355 toproduce an electrical signal output 244 for driving motor 222controlling a variable transformer 226. 220-volt AC power is applied viaconductors 235 and 236 through switch 230 to the primary winding 232 ofvariable transformer 226. The secondary winding 234 applies a variableAC voltage via conductors 239 and 240 to the DC rectifier 224 shown inFIG. 9, for the purposes hereinbefore described. Motor 222 mechanicallychanges the coupling between the primary and secondary windings, 232 and234, respectively, of variable transformer 226 for varying the ACvoltage applied to the DC rectifier 224 in response to the integratedflow rate and color signals provided by flow meter 36 and color meter38.

Referring now to FIG. 12, 220-volt AC is applied via conductors 209 and211 through a switch 256 as an input to the third control circuit 218.220-volt AC power is applied via conductor 209 and 365 to amplifier 364.The electrical signals generated by flow meter 36 (see FIG. 9) areapplied via conductor 248 as an input to amplifier 364. The amplifiedoutput of amplifier 364 is applied via conductor 369 to relay coil 371,and via conductor 367 as one input to an integrating circuit 374. Whencoil 371 is energized, relay contacts 373 close thereby energizing theremainder of the third control circuit 218.

With relay contacts 373 closed, power is applied via conductors 209 and375 to amplifier 366, via conductors 209, 376 and 379 as an input to aconventional bridge and amplifier circuit 368, via conductors 209, 376and 380 to amplifier 370, and via conductors 209 and 376 as an input toamplifier 372. The electrical output of color meter 62 is applied viaconductor 270 to amplifier 366 whose output signal is applied viaconductor 378 as a second input to integrating circuit 374. Theelectrical signal output of resistivity meter 64 is applied viaconductor 271 to the conventional Wheatstone bridge and amplifiercircuit 368. The output of the bridge and amplifier circuit 368 isapplied via conductor 381 as a third input to integrating circuit 374.Integrating circuit 374 integrates the amplified flow rate, color andresistivity signals for generating an electrical signal applied viaconductor 276 to motor 258 for mechanically varying the coupling betweenthe windings of variable transformer 260. 220-volt AC power is appliedvia conductors 261 and 263 through switch 262 to the primary winding 259of variable transformer 260. Secondary winding 264 applies a variable ACsignal via conductors 265 and 266 to the DC rectifier 267 as hereinabovedescribed. Motor 258 mechanically varies the coupling between theprimary and secondary windings, 259 and 264, respectively, to vary theAC voltage to the DC rectifier 267 in order to vary the DC voltageproduced by rectifier 267 and applied to the electrodes 150 of theelectrode tank assembly 70 for the purposes hereinabove described.

F loc height sensor 74 of the second electrode tank assembly 70 operatesin the identical manner hereinbefore described for the previous flocheight sensors. An electrical signal is applied via conductor 272 as aninput to amplifier 370, and then applied via conductor 382 to a relaycoil 384, which when energized maintains relay contacts 385 in an openposition. When the proper floc bed depth is reached, coil 384 isdeenergized, closing relay contacts 385 and applying AC power viaconductors 209, 376, 383 and 274 to relay coil 424 of solenoid valve128. Upon energization of relay coil 424, valve 128a is actuated toallow floc precipitate in the bottom of electrode tank 72 to bedischarged through pipe 125. Similarly, when the iloc height sensor 86of the second fioc settling tank 84 is actuated, an electrical signal isapplied via conductor 273 to amplifier 372, whose output is applied viaconductor 387 to a relay coil 388. Energization of relay coil 388maintains relay contacts 389 in an open condition until the proper flocbed height is reached, whereupon coil 388 is deenergized and applies ACpower via conductors 209, 376, 386, and 275 to relay coil 425 ofsolenoid valve 130. Relay coil 425 actuates valve 130a to allow disposalof a portion of the floc precipitate in floc settling tank 84 throughpipe 129 to the fioc accumulation tank 110 as hereinabove described.

FIG. 13 is a schematic of the fourth control circuit showing 220 voltsAC applied via conductor 277 and 279 and through switch 278 as an inputto the control circuit 220. The AC power is applied through switch 278via conductors 277 and 391 to amplifier 390. Electrical signals fromflow meter 36 (see FIG. 1) are applied via conductor 254 (see FIG. 9) asa second input to amplifier 390. The output of amplifier 390 is appliedvia conductor 397 to the relay coil 401, which when energized closescontacts 403 and applies electrical power via conductor 277, switch 278,conductor 393, closed contacts 403 and conductor 404 to amplifier 392,and via the closed contacts 403 and conductors 430 and 406 to aconventional bridge and amplifier circuit 394'. Electrical power is alsoapplied through the closed contacts 403 via conductors 430 and 408 toamplifier 396 and via conductor 430 to open relay con tacts 415 and 417.The output of amplifier 390 is also applied via conductor 399 as aninput to a first conventional integrator circuit 400 and via conductor395 to a second conventional integrating circuit 402. The electricalsignal output of color meter 90 is applied via conductor 294 toamplifier 392 whose output is applied via conductor 405 as a secondinput to integrating circuit 402.

The electrical signal output generated by the resistivity meter 92 isapplied via conductor 295 as an input to the conventional Wheatstonebridge and amplifier circuit 394, the output of which is applied viaconductor 407 to integrating circuit 402 as a third input. The amplifiedsignals representing the flow rate of the water, the color of the water,and the resistivity of the water are integrated by the conventionalintegrating circuit 402 and produce an output signal applied viaconductor 300 to motor 282. Motor 282 mechanically varies the couplingbetween the primary and the secondary windings, 286 and 287,respectively, of variable transformer 281 for applying a variable ACvoltage to DC rectifier 284 for controlling the electrical power appliedto the oxidant generator assembly 104 (see FIG. 9) depending on theoxidant demands,

which in turn are dependent upon the flow rate, the color and theresistivity of the treated water. AC power is applied via conductors 288and 289 through switch 280 to the primary winding'286 of variabletransfonner 281, while the variable secondary AC voltage is applied viaconductors 290 and 291 from secondary winding 287 to DC rectifier 284(see FIG. 9) for the purposes hereinbefore described. In addition, ACpower is applied via conductors 288 and 289, switch 280 and conductors283 and 285 to pump 196 within the oxidant generator assembly 104 (seeFIG. 6).'Simultaneously with operating motor 282 via signals appliedthrough conductor 300, integrating circuit 402 applies an electricalvoltage via conductor 299 to operate pump 142 for cycling water from thefinishing pond to the oxidant generator assembly 104 and absorbing thedesired oxidant and applying it to the pH and oxidant adjustment tank 96as hereinabove described in the system shown in FIG. 1.

The pH meter 94, typically a conventional glass electrode device,applies an electrical signal via conductor 296 to amplifier 396. Theoutput of amplifier 396 is applied via conductor 409 to a signaldiscriminator circuit 398 for detecting'a signal level applied above orbelow a preset minimum level representing the desired pH of the treatedwater. The output of the conventional discriminator 398 is applied to anintegrating circuit 400 via conductor 410 and is integrated with theflow meter signal from amplifier 390, applied via conductor 399, toproduce an output signal at either conductor 411 or 412 from integrator400. If the pH of the water is caustic and acid needs to be added, anoutput signal will appear at conductor 411 of the integrator circuit 400and be applied to the relay coil 414, which when energized closes relaycontacts 415 thereby applying voltage to the acid pump 117 via conductor297. Pump 117 moves acid solution from acid tank 108 through pipes and131 to the pH and oxidant adjustment tank 96 as hereinbefore described(see FIG. 1). By the same token, if the pH as monitored by meter 94 isshown to be acid and a caustic needs to be added, an output will appearat conductor 412 of integrator 400 and be applied to relay coil 416.When relay coil 416 is energized, relay contacts 417 are closed therebyapplying voltage via conductor 430, closed relay contacts 417 andconductor 298 to the caustic pumpl38 for pumping caustic solutionthrough pipe 137-to the pH and oxygen adjustment tank 96, as hereinabovedescribed (see FIG. 1).

With the addition of the acid or caustic solution, the pH of the waterchanges, thus changing the electrical signal applied via conductor 296from pH meter 94. When the pH has reached the desired level, theintegrator 400 output will reach a preset level, thus deenergizing coils414 or 416 and opening the closed contacts 415 or 417 to shut ofi theappropriate acid or caustic pump 117 or 138.

As hereinbefore mentioned, in some systems for treating polluted water,only one electrode tank assembly and floc settling tank will benecessary for full treatment of the water. On the other hand, for otherinstallations, it may be necessary to utilize a third or fourth set ofelectrode tank assemblies and H00 settling tanks, depending on thecondition of the water and the pollutants that must be removed.Accordingly, additional control circuitry would be needed, but wouldfunction in the same manner as the control circuitry described.

Many types of polluted waters have been. successfully treated utilizingthe system hereinbefore described, and an example of the operation ofthe system on an extremely polluted combination of waters will herein begiven. The polluted waste water to be treated contains black liquoreffluent from a paper mill mixed in combination with house servicesewage and wastes from a tannery. Since the combination of the pollutedwaste waters above described will contain quite a bit of ABS 7(alkyl-benzene-sulfonate) or detergents, the embodiment of thepreliminary treatment tank assembly as shown in FIG. 7 will be utilizedin place of the preliminary treatment tank 26 shown in FIG. 1 forpurposes to be hereinafter discussed.

2. The process described in claim 1, including the additional steps ofinitially measuring the resistivity of the waste water after the initialpH adjustment and first floc precipitation, and adjusting theresistivity of the waste water to a predetermined value in response tosaid initial resistivity measurement.
 3. The process described in claim2, including the additional steps of initially determining the color ofthe waste water after said initial resistivity measurement andadjustment, and adjusting said predetermined quantity of saidpreselected floc precipitate initially mixed with said pH adjusted wastewater for controlling said first precipitation of materials from thewaste water for adjusting the color of the water to a predeterminedvalue.
 4. The process described in claim 1, including the additionalsteps of measuring the quantity of said first precipitate materialobtained from the waste water, removing the excess of said firstprecipitate material exceeding a predetermined measured quantity, anddrying said removed excess first precipitate material and said removedfoamed colloidal material for reclaiming valuable minerals and othermaterials therefrom.
 5. The process described in claim 1, including theadditional steps of measuring the quantity of said second and thirdprecipitate materials obtained from the waste water, removing the excessof said second and third precipitate materials exceeding predeterminedmeasured quantities of each of said materials, and storing said excessof said second and third precipitate materials for use as saidpreselected floc precipitate initially mixed with said pH adjustedwater.
 6. The process described in claim 5, including the additionalsteps of measuring the quantity of said second and third precipitatematerials stored for use as said preselected floc precipitate initiallymixed with said pH adjusted water, removing the excess of said storedsecond and third precipitate materials exceeding a predeterminedmeasured quantity, and drying said removed excess second and thirdprecipitate material for reclaiming valuable minerals and othermaterials therefrom.
 7. The process described in claim 3, including theadditional steps of performing a second measurement of resistivity ofthe water, performing a second determination of color of the water,measuring the volume and flow rate of waste water being treated, andgenerating said predetermined quantity of said preselected oxidant inresponse to said respective volume, flow rate and resistivitymeasurements and said color determination.
 8. The process described inclaim 7, wherein the step of generating said selected oxidant furthergenerates preselected acid and caustic solutions for use in adjustingthe pH of the waste water.
 9. The process described in claim 1,including the additional step of allowing the water and said dissolvedoxidant to stand quiesently for a predetermined time period forpermitting said oxidant additional time in which to act on bacteria,oxygen demanding and odor causing organic materials and other pollutantsprior to discharge.
 10. The process described in claim 1, including theadditional steps of providing a bubble curtain of compressed air throughwhich the initially pH adjusted water mixed with said predeterminedquantity of said preselected floc precipitate must pass for floatingcoalesced colloidal material and other pollutants to the surface of thewater as a floating foam, removing said foam of coalesced colloidalmaterial and other pollutants from the waste water surface prior to saidwaste water Being subjected to said electrical current, and drying saidremoved foamed colloidal materials for reclaiming valuable minerals andother materials therefrom.
 11. A waste water treatment process forremoving colloidal, oxygen demanding and odor causing organic materials,inorganic materials and other pollutants from the water, comprising thesteps of initially measuring the pH of the waste water, initiallyadjusting the pH of the waste water to a predetermined value in responseto said initial measurement, initially mixing a predetermined quantityof a preselected floc precipitate with said pH adjusted waste water forcausing a first precipitation of materials from the waste water,initially measuring the resistivity of the waste water, adjusting theresistivity of the waste water to a predetermined value in response tosaid initial resistivity measurement, initially determining the color ofthe waste water, adjusting said predetermined quantity of saidpreselected floc precipitate initially mixed with said pH adjusted wastewater for controlling said first floc precipitation of materials fromthe waste water for adjusting the color of the water to a predeterminedvalue, subjecting the waste water to a predetermined density ofelectrical current flow between at least a pair of electrodes ofpreselected materials for electrostatically charging the colloidalmaterials in the waste water, said electrostatically charged colloidalmaterials coalescing and floating to the surface of the waste water bythe interaction of oxygen and hydrogen bubbles evolved at saidelectrodes for forming a floating foam on the surface of the water, saidelectrical current flow between said electrodes releasing ions of thepreselected electrode materials for causing a second floc precipitationof materials from the waste water and acting to destroy oxygen demandingorganic materials, bacteria and viruses, said oxygen bubbles evolvedfrom at least one electrode acting to oxidize organic odor and colorcausing materials in the water, removing the floating foamed colloidalmaterial from the surface of the water, transferring the waste water anda portion of said second floc precipitate of materials to an arearemoved from the action of said electrical current for circulating thewater through said portion of said second floc precipitate for causing athird floc precipitation of materials from the water, transferring saidcirculated water and a portion of said second and third flocprecipitates through which the water has circulated to an area ofsubstantial quiescence where said portion of said second and third flocprecipitates causes a fourth floc precipitation of materials from thewater, withdrawing the waste water substantially free of flocprecipitate from said quiescent area, performing a second measurement ofpH and resistivity and a second determination of color of the water,adjusting the pH of the water in response to said second pH measurement,dissolving a preselected oxidant in predetermined quantities with thewater for further adjusting the resistivity and color of the water inresponse to said second measurement of resistivity and said seconddetermination of color, said oxidant further killing bacteria andreducing the oxygen demanding and odor causing organic materialsremaining in the water.
 12. The process described in claim 11, includingthe additional steps of measuring the quantity of said first flocprecipitate material obtained from the waste water, removing the excessof said first floc precipitate material exceeding a predeterminedmeasured quantity, and drying said removed excess first floc precipitatematerial and said removed foamed colloidal material for reclaimingvaluable minerals and other materials therefrom.
 13. The processdescribed in claim 11, including the additional steps of measuring thequantity of said second floc material Precipitate obtained from thewater, measuring the excess of said second floc precipitate exceedingpredetermined measured quantities of said material, and storing saidexcess of said second floc precipitate materials for use as saidpreselected floc precipitate initially mixed with said pH adjustedwater.
 14. The process described in claim 11, including the additionalsteps of measuring the quantity of said fourth floc precipitate ofmaterials obtained from the water, removing the excess of said fourthfloc precipitate materials exceeding a predetermined measured quantityof said fourth precipitate material, and storing said excess of saidfourth floc precipitate with said second floc precipitate material foruse as said preselected floc precipitate initially mixed with said pHadjusted water.
 15. The process described in claim 14, including theadditional steps of measuring the quantity of said second and fourthfloc precipitate materials stored for use as said preselected flocprecipitate initially mixed with said pH adjusted water, removing theexcess of said stored second and fourth floc precipitate materialsexceeding a predetermined measured quantity, and drying said removedexcess second and fourth floc precipitate materials for reclaimingvaluable minerals and other materials therefrom.
 16. The process asdescribed in claim 11, including the additional steps of measuring thevolume and flow rate of the waste water under treatment, and generatingsaid predetermined quantity of said preselected oxidant in response tosaid respective volume, flow rate and second resistivity measurementsand said second color determination.
 17. The process as described inclaim 16, wherein the step of generating said selected oxidant furthergenerates preselected acid and caustic solutions for use in adjustingthe pH of the waste water.
 18. The process described in claim 11,including the additional step of allowing the water and said dissolvedoxidant to stand quiescently for a predetermined time period forpermitting said oxidant additional time in which to act on bacteria,oxygen demanding and odor causing organic materials and other pollutantsprior to discharge.
 19. The process described in claim 11, including theadditional steps of providing a bubble curtain of compressed air throughwhich the initially pH adjusted water mixed with said predeterminedquantity of said preselected floc precipitate must pass for floatingcoalesced colloidal material and other pollutants to the surface of thewater as a floating foam, removing said foam of coalesced colloidalmaterial and other pollutants from the waste water surface prior to saidwaste water being subjected to said electrical current, and drying saidremoved foamed colloidal material for reclaiming valuable minerals andother materials therefrom.
 20. Apparatus for removing colloidal, oxygendemanding and odor causing organic materials, inorganic materials andother pollutants from waste water, comprising a preliminary treatmenttank for initially admitting the waste water, first pH measurement meansfor measuring the pH of the waste water admitted into said tank, firstpH adjustment means cooperating with said preliminary treatment tank forinitially adjusting the pH of the waste water therein to a predeterminedvalue in response to said first pH measurement, means cooperating withsaid preliminary treatment tank for initially mixing a predeterminedquantity of a preselected floc precipitate with said pH adjusted wastewater in said preliminary treatment tank for causing a firstprecipitation of materials from the waste water, means for dischargingthe waste water substantially free of said precipitate materials fromsaid preliminary treatment tank, an electrode tank assembly forreceiving said waste water from said preliminary treatment tank andsubjecting the water to a predetermined density of Electrical currentflow between at least a pair of electrodes of preselected materials forelectrostatically charging the colloidal materials in the waste water,said electrostatically charged colloidal materials coalescing andfloating to the surface of the waste water and the top surface of saidelectrodes by the interaction of oxygen and hydrogen bubbles evolved atsaid electrodes for forming a floating foam on the surface of the waterand the top surface of said electrodes, said electrical current flowbetween said electrodes releasing ions of the preselected electrodematerials for causing a second precipitation of materials from the wastewater, said ions of the preselected electrode materials further actingto destroy oxygen demanding organic materials, bacteria and viruses,said oxygen bubbles evolved from at least one electrode further actingto oxidize organic odor and color causing materials in the water, wipingmeans for wiping the top surface of said electrodes for removing thefloating foamed colloidal material from the surface of the water and thetop surface of said electrodes, means for discharging the waste waterand a portion of said second precipitate of materials from saidelectrode tank, a floc settling tank for receiving the waste water andsaid portion of said second precipitate of materials and allowing thewater to quiescently accumulate with said portion of said secondprecipitate for causing a third precipitation of materials from thewaste water, means for discharging the water substantially free ofprecipitate materials from said floc settling tank, a pH and oxidantadjustment tank for receiving the water substantially free ofprecipitate materials from said floc settling tank, second pHmeasurement means for measuring the pH of the water discharged from saidfloc settling tank, second pH adjustment means cooperating with said pHand oxidant adjustment tank for adjusting the pH of the water therein toa predetermined value in response to said second pH measurement, asource of a preselected oxidizing material, means for transferring apredetermined quantity of said oxidizing material to said pH and oxidantadjustment tank and dissolving said predetermined quantity of saidpreselected oxidant with the water for killing bacteria and reducing theoxygen demanding color, and odor causing organic material remaining inthe water.
 21. The apparatus as described in claim 20, wherein saidfirst pH adjustment means comprises a source of a preselected acidsolution interconnected to said preliminary treatment tank, a source ofa preselected caustic solution interconnected to said preliminarytreatment tank, and a pair of pumps, one of which is disposed in theinterconnection between said acid solution source and the other of whichis disposed in the interconnection between said caustic solution sourceand said preliminary treatment tank, each of said pumps being operableby control circuit means responsive to said first pH measurement. 22.The apparatus as described in claim 20, wherein said wiping meanscomprises a drive shaft having spaced chain sprockets and a drivesprocket disposed thereon, means cooperating with said drive sprocket torotate said drive shaft, an idler shaft horizontally spaced from saiddrive shaft and having spaced chain sprockets disposed thereon inalignment with said chain sprockets of said drive shaft, a pair ofchains, one of which is disposed between corresponding pairs of alignedchain sprockets on said drive and idler shafts for forming a pair ofspaced parallel driven chains, a plurality of paddle blades, each havinga flexible non-conducting blade edge, each of said blades being fixedhorizontally between said parallel driven chains for continuoushorizontal movement with said driven chains, and a frame assemblyattached to said electrode tank for supporting said drive and idlershafts spaced aBove the top surface of said electrodes for allowing thenon-conducting blade edges of said paddle blades to sweep longitudinallyacross the top surface of said electrodes and remove said floatingfoamed colloidal material.
 23. The apparatus as described in claim 20,wherein said means for discharging the waste water and a portion of saidsecond precipitate materials from said electrode tank comprises aplurality of vertically spaced discharge pipes communicating with theinterior of said electrode tank each having a valve means forcontrolling the flow of water and a portion of said second precipitatematerials through each pipe from said electrode tank, and a dischargemanifold receiving the waste water and controlled quantity of saidsecond precipitate material for transfer to said floc settling tank. 24.The apparatus as described in claim 20, including an injection manifoldreceiving said waste water from said means for discharging said watersubstantially free of said precipitate materials from said preliminarytreatment tank, and a plurality of vertically spaced injection pipesinterconnecting said manifold and said electrode tank assembly foruniform distribution of the water over the entire height of theelectrodes in said electrode tank assembly.
 25. The apparatus asdescribed in claim 20, wherein said means for discharging the watersubstantially free of precipitate materials from said floc settling tankcomprises a weir disposed at one end of said tank into which saidquiescently accumulating water spills when the water has reached apreselected depth, and means for discharging the water from said weir.26. The apparatus as described in claim 21, wherein said second pHadjustment means includes said sources of preselected acid and causticsolutions as utilized in said first pH adjustment means, interconnectingpiping connecting each of said sources of acid and caustic solution tosaid pH and oxidant adjustment tank, and a pair of pumps, one of whichis disposed in the interconnection between said acid source and theother of which is disposed in the interconnection between said causticsolution source and said pH and oxidant adjustment tank, said pumpsoperable by control circuit means responsive to said second pHmeasurement.
 27. The apparatus described in claim 20, including firstresistivity measurement means for measuring the resistivity of the wastewater after the initial pH adjustment and first inorganic precipitate insaid tank, and means for recycling a portion of the water substantiallyfree of floc precipitate discharged from said floc settling tank into amixing tank compartment of said preliminary treatment tank for adjustingthe resistivity of the waste water to a predetermined value in responseto said first resistivity measurement.
 28. The apparatus described inclaim 27, including first color measurement means for determining thecolor of the waste water discharged from said preliminary treatmenttank, and means responsive to said color measurement means for adjustingsaid predetermined quantity of said preselected floc precipitatetransferred from said floc precipitate source for initial mixing withsaid pH adjusted waste water in said preliminary treatment tank forcontrolling said first precipitation of materials from the waste waterand adjusting the color of the water to a predetermined value.
 29. Theapparatus as described in claim 28, wherein said means responsive tosaid color measurement means for adjusting said predetermined quantityof said preselected floc precipitate utilized for initial mixing withthe pH adjusted waste water comprises a source of said preselected flocprecipitate interconnected with said preliminary treatment tank, and apump disposed in said interconnection between said source of preselectedfloc precipitate and said preliminary treatment tank and operable bycontrol circuit means responsive to saId first color measurement means.30. The apparatus as described in claim 20, including first precipitatemeasuring means for measuring the quantity of said first materialprecipitated in said preliminary treatment tank, means for removing theexcess of said first precipitate material exceeding a predeterminedquantity measured by said first precipitate measuring means, and meansfor receiving and drying said removed excess of said first precipitatematerial and said removed foamed colloidal material for allowingreclamation of valuable minerals and other materials therefrom.
 31. Theapparatus as described in claim 20, including second precipitatemeasuring means for measuring the quantity of said second materialprecipitated in said electrode tank, third precipitate measuring meansfor measuring the quantity of said third material precipitated in saidfloc settling tank, means for removing the excess of said second andthird precipitate materials from said electrode floc settling tanks whensaid second and third precipitates exceed a predetermined measuredquantity as measured by said second and third precipitate measuringmeans, and transferring said excess of said second and third precipitatematerials to said floc precipitate source for storage and reuse.
 32. Theapparatus as described in claim 31, including fourth precipitatemeasuring means for measuring the quantity of said precipitate materialsstored in said floc precipitate source, means for removing the excess ofsaid stored precipitate materials exceeding a predetermined quantitymeasured by said fourth precipitate measuring means, and means forreceiving and drying said removed excess of said precipitate materialfor reclamation of valuable minerals and other materials therefrom. 33.The apparatus as described in claim 20, including means for measuringthe volume and flow rate of the waste water, second resistivitymeasurement means for measuring the resistivity of the water dischargedfrom said floc settling tank, second color determination means fordetermining the color of the water discharged from said floc settlingtank, oxidant generating means for generating a predetermined quantityof said preselected oxidizing material in response to said volume, flowrate and said second resistivity measurement and said second colordetermination.
 34. The apparatus as described in claim 33, wherein saidoxidant generating means also generates a continuous supply of saidpreselected acid and caustic solutions, and further includes means fortransferring said generated acid and caustic solutions to said sourcesfor storage.
 35. The apparatus as described in claim 20, furtherincluding a polishing pond for receiving the water discharged from saidpH and oxidant adjustment tank for allowing the water and said dissolvedoxidant to stand quiescently for a predetermined time period forpermitting said oxidant additional time in which to act on bacteria,oxygen demanding and odor causing organic materials and other pollutantsprior to discharge.
 36. The apparatus as described in claim 20, furtherincluding a source of compressed air, porous means disposed in thebottom of said preliminary treatment tank for receiving air from saidcompressed air tank and producing a vertical bubble curtain within saidpreliminary treatment tank through which the initially pH adjusted watermixed with said predetermined quantity of said preselected flocprecipitate must pass for floating coalesced colloidal material andother pollutants to the surface of the water as a floating foam, andsweeping means for sweeping the top surface of the waste water in saidpreliminary treatment tank for removing said foam of coalesced colloidalmaterial and other pollutants from the waste water prior to thedischarge of the waste water into said electrode tank.
 37. The apparatusas described in claim 36, wherein said porous means comprises anelongated block Of porous material extending across the bottom of saidpreliminary treatment tank.
 38. The apparatus as described in claim 36,wherein said sweeping means includes a drive shaft having spaced chainsprockets and a drive sprocket disposed thereon, means cooperating withsaid drive sprocket to rotate said drive shaft, an idler shafthorizontally spaced from said drive shaft and having spaced chainsprockets disposed thereon in alignment with said chain sprockets ofsaid drive shaft, a pair of chains, one of which is disposed betweencorresponding pairs of aligned chain sprockets on said drive and idlershafts for forming a pair of spaced parallel driven chains, a pluralityof paddle blades fixed horizontally between said parallel driven chainsfor continuous horizontal movement with said driven chains, and a frameassembly attached to said preliminary treatment tank for supporting saiddrive and idler shafts spaced above the surface of the water in saidtank for allowing said paddle blades to sweep longitudinally across thewater surface and remove said floating foamed colloidal material. 39.Apparatus for removing colloidal, oxygen demanding and odor causingorganic materials, inorganic materials and other pollutants from wastewater, comprising a preliminary treatment tank for initially admittingthe waste water, first pH measurement means for measuring the pH of thewaste water admitted into said tank, first pH adjustment meanscooperating with said preliminary treatment tank for initially adjustingthe pH of the waste water therein to a predetermined value in responseto said first pH measurement, a source of a preselected flocprecipitate, means interconnected between said preliminary treatmenttank and said source of preselected floc precipitate for controlling thequantity of said floc precipitate mixed with said waste water in saidpreliminary treatment tank for causing a first precipitation ofmaterials from the waste water, means for discharging the waste watersubstantially free of said precipitate materials from said preliminarytreatment tank, means for measuring the volume and flow rate of thewaste water, first color determination means for determining the colorof the waste water discharged from said preliminary treatment tank,control circuit means responsive to said first color determination meansfor controlling said means interconnected between said preliminarytreatment tank and said floc precipitate for adjusting the color of thewaste water to a predetermined value, an electrode tank assembly forreceiving said waste water from said mixing tank and subjecting thewater to a predetermined density of electrical current flow between atleast a pair of electrodes of preselected materials forelectrostatically charging the colloidal materials in the waste water,said electrostatically charged colloidal materials coalescing andfloating to the surface of the waste water and the top surface of saidelectrodes by the interaction of oxygen and hydrogen bubbles evolved atsaid electrodes for forming a floating foam on the surface of the waterand the top surface of said electrodes, said electrical current flowbetween said electrodes releasing ions of the preselected electrodematerials for causing a second precipitation of materials from the wastewater, said ions of the preselected electrode materials further actingto destroy oxygen demanding organic materials, bacteria and viruses,said oxygen bubbles evolved from at least one electrode further actingto oxidize organic odor causing materials in the water, wiping means forwiping the top surface of said electrodes for removing the floatingfoamed colloidal material from the surface of the water and the topsurface of said electrodes, means for discharging the waste water and aportion of said second precipitate of materials from said electrodetank, a floc settling tank for receiving thE waste water and saidportion of said second precipitate of materials, circulating the waterthrough said second precipitate for causing a third precipitation ofmaterials and thereafter allowing the water and a portion of said thirdprecipitate to quiescently accumulate with said portion of said thirdprecipitate for causing a fourth precipitation of materials from thewaste water, means for discharging the water substantially free of anyprecipitate materials from said floc settling tank, a pH and oxidantadjustment tank for receiving the water substantially free ofprecipitate materials from said floc settling tank, second pHmeasurement means for measuring the pH of the water discharged from saidfloc settling tank, second pH adjustment means cooperating with said pHand oxidant adjustment tank for adjusting the pH of the water therein toa predetermined value in response to said second pH measurement, asource of a preselected oxidizing material, means for transferring apredetermined quantity of said oxidizing material to said pH and oxidantadjustment tank and dissolving said predetermined quantity of saidpreselected oxidant with the water for killing bacteria and reducing theoxygen demanding and odor causing organic material remaining in thewater.
 40. The apparatus as described in claim 39, wherein said first pHadjustment means comprises a source of a preselected acid solutioninterconnected to said preliminary treatment tank, a source of apreselected caustic solution interconnected to said preliminarytreatment tank, and a pair of pumps, one of which is disposed in theinterconnection between said acid solution source and the other of whichis disposed in the interconnection between said caustic solution sourceand said preliminary treatment tank, each of said pumps being operableby control circuit means responsive to said first pH measurement. 41.The apparatus as described in claim 40, wherein said electrode tankcomprises a rectangular tank structure having an integral bottom andopen top, a plurality of rectangular spaced-apart electrodes verticallyoriented and disposed within said tank structure with opposite ends ofsuccessive ones of said electrodes contacting opposite walls of saidtank structure for providing an alternating baffled path for the wastewater moving through said electrode tank and to provide the waste watermaximum exposure time to the current between adjacent electrodes, andcontrol circuit means connected to each of said electrodes forcontrolling the density of electrical current flow between saidelectrodes in response to said volume, flow rate and color measurements.42. The apparatus as described in claim 41, wherein said wiping meanscomprises a drive shaft having spaced chain sprockets and a drivesprocket disposed thereon, means cooperating with said drive sprocket torotate said drive shaft, an idler shaft horizontally spaced from saiddrive shaft and having spaced chain sprockets disposed thereon inalignment with said chain sprockets of said drive shaft, a pair ofchains, one of which is disposed between corresponding pairs of alignedchain sprockets on said drive and idler shafts for forming a pair ofspaced parallel driven chains, a plurality of paddle blades, each havinga flexible non-conducting blade edge, each of said blades being fixedhorizontally between said parallel driven chains for continuoushorizontal movement with said driven chains, a frame assembly attachedto said electrode tank for supporting said drive and idler shafts spacedabove the top edge surface of said electrodes for allowing thenon-conducting blade edges of said paddle blade to sweep longitudinallyacross the top edge surface of said electrodes and remove said floatingfoamed colloidal material.
 43. The apparatus as described in claim 42,wherein said means for discharging the waste water and a portion of saidsecond precipitate of materials from said electrode tank comprises aplurality of vertically spaced discharge pipes communicating with theinterior of said electrode tank each having a valve means forcontrolling the flow of water and a portion of said second precipitatematerials through each pipe from said electrode tank, and a dischargemanifold receiving the waste water and controlled quantity of saidsecond precipitate material for transfer to said floc settling tank. 44.The apparatus as described in claim 43, including an injection manifoldreceiving said waste water from said means for discharging said watersubstantially free of said precipitate materials from said preliminarytreatment tank, and a plurality of vertically spaced injection pipesinterconnecting said manifold and said electrode tank assembly foruniform distribution of the water over the entire height of theelectrodes in said electrode tank assembly.
 45. The apparatus asdescribed in claim 44, wherein said floc settling tank comprises arectangular tank structure having an integral bottom, a first partitionplate fixed between opposite side walls of said tank structure andadjacent one end of said tank for defining a first vertical compartment,the bottom end of said plate spaced from said bottom of said tank andspaced a greater distance from said one end of said tank than the topend of said plate, a second partition plate fixed between opposite sidewalls of said tank structure and spaced from said first plate toward theother end of said tank for defining a second vertical compartmentbetween said first and second plates, the bottom end of said secondplate sealingly fixed to said bottom of said tank with the top end ofsaid second plate spaced downwardly from the top edges of the side wallsof said tank, said top end of said second plate slanting slightly towardsaid one end of said tank, a third partition plate fixed verticallybetween opposite side walls of said tank structure and spaced from saidsecond plate toward the other end of said tank for defining a thirdvertical compartment between said second and third plates and a fourthcompartment between said third plate and the other end of said tank, thebottom end of said third plate spaced from said bottom of said tank forpermitting communication between said third and fourth compartments, aT-shaped pipe disposed in said first compartment with the cross-part ofthe T-shaped pipe being positioned adjacent said tank bottom and havingapertures facing said one end for discharging the waste water and saidsecond precipitate into the bottom of said first compartment where thewater circulates through said second precipitate and up into said secondcompartment for causing a third precipitation of said materials, saidwater filling said second compartment and gently spilling over the topend of said second plate into said third compartment and carrying aportion of said third precipitate into said third compartment, saidwater filling said third and fourth compartments and passing throughsaid accumulated portion of said third precipitate present in said thirdand fourth compartments for causing a fourth material precipitation tooccur in said third and fourth compartments.
 46. The apparatus asdescribed in claim 45, wherein said means for discharging the watersubstantially free of precipitate materials from said floc settling tankcomprises a weir disposed at said other end of said tank at apreselected height into which said accumulating water spills when thewater has reached said preselected height, and means for discharging thewater from said weir.
 47. The apparatus as described in claim 46,wherein said second pH adjustment means includes said sources ofpreselected acid and caustic solutions as utilized in said first pHadjustment means, interconnecting piping connecting each of said sourcesof acid and caustic solution to said pH and oxidant adjuStment tank, anda pair of pumps, one of which is disposed in the interconnection betweensaid acid solution source and the other of which is disposed in theinterconnection between said caustic solution source and said pH andoxidant adjustment tank, said pumps operable by control circuit meansresponsive to said second pH measurement.
 48. The apparatus described inclaim 47, including first resistivity measurement means for measuringthe resistivity of the waste water after the initial pH adjustment andfirst inorganic floc precipitate in said tank, and means for recycling aportion of the water substantially free of floc precipitate dischargedfrom said floc settling tank into a mixing tank compartment of saidpreliminary treatment tank for adjusting the resistivity of the wastewater to a predetermined value in response to said first resistivitymeasurement.
 49. The apparatus as described in claim 48, wherein saidmeans responsive to said color measurement means for adjusting saidpredetermined quantity of said preselected floc precipitate utilized forinitial mixing with the pH adjusted waste water comprises a pumpdisposed in said interconnection between said source of preselected flocprecipitate and said preliminary treatment tank and operable by saidcontrol circuit means responsive to said first color measurement means.50. The apparatus as described in claim 49, including first precipitatemeasuring means for measuring the quantity of said first materialprecipitated in said preliminary treatment tank, means for removing theexcess of said first precipitate material exceeding a predeterminedquantity measured by said first precipitate measuring means, and meansfor receiving and drying said removed excess of said first precipitatematerial for allowing reclamation of valuable minerals and otherinorganic materials therefrom.
 51. The apparatus as described in claim50, including second precipitate measuring means for measuring thequantity of said second material precipitated in said electrode tank,third precipitate measuring means for measuring the quantity of saidfourth material precipitated in said floc settling tank, means forremoving the excess of said second and fourth precipitate materials fromsaid electrode and floc settling tanks when said second and fourthprecipitates exceed a predetermined quantity measured by said second andthird precipitate measuring means, and transferring said excess of saidsecond and fourth precipitate materials to said floc precipitate sourcefor storage and reuse.
 52. The apparatus as described in claim 51,including fourth precipitate measuring means for measuring the quantityof said precipitate materials stored in said floc precipitate source,means for removing the excess of said stored precipitate materialsexceeding a predetermined quantity measured by said fourth precipitatemeasuring means, and means for receiving and drying said removed excessof said precipitate materials for reclamation of valuable minerals andother materials therefrom.
 53. The apparatus as described in claim 52,including second resistivity measurement means for measuring theresistivity of the water discharged from said floc settling tank, secondcolor determination means for determining the color of the waterdischarged from said floc settling tank, and oxidant generating meansfor generating a predetermined quantity of said preselected oxidizingmaterial in response to said volume, flow rate and said secondresistivity measurement and said second color determination.
 54. Theapparatus as described in claim 53, wherein said oxidant generatingmeans also generates a continuous supply of said preselected acid andcaustic solutions, and further includes means for transferring saidgenerated acid and caustic solutions to said sources for storage. 55.The apparatus as described in claim 54, further including a polishingpond for receiving the water discharged from said pH and oxidantadjustment tank for allowing the water and said dissolved oxidant tostand quiescently for a predetermined time period for permitting saidoxidant additional time in which to act on bacteria, oxygen demandingand odor causing organic materials and other pollutants prior todischarge.
 56. The apparatus as described in claim 39, further includinga source of compressed air, porous means disposed in the bottom of saidpreliminary treatment tank for receiving air from said compressed airtank and producing a vertical bubble curtain within said preliminarytreatment tank through which the initially pH adjusted water mixed withsaid predetermined quantity of said preselected floc precipitate mustpass for floating coalesced colloidal material and other pollutants tothe surface of the water as a floating foam, and sweeping means forsweeping the top surface of the waste water in said preliminarytreatment tank for removing said foam of coalesced colloidal materialand other pollutants from the waster water prior to the discharge of thewaste water into said electrode tank.
 57. The apparatus as described inclaim 56, wherein said porous means comprises an elongated block ofporous material extending across the bottom of said preliminarytreatment tank.
 58. The apparatus as described in claim 57, wherein saidsweeping means includes a drive shaft having spaced chain sprockets anda drive sprocket disposed thereon, means cooperating with said drivesprocket to rotate said drive shaft, an idler shaft horizontally spacedfrom said drive shaft and having spaced chain sprockets disposed thereonin alignment with said chain sprockets of said drive shaft, a pair ofchains, one of which is disposed between corresponding pairs of alignedchain sprockets on said drive and idler shafts for forming a pair ofspaced parallel driven chains, a plurality of paddle blades fixedhorizontally between said parallel driven chains for continuoushorizontal movement with said driven chains, and a frame assemblyattached to said preliminary treatment tank for supporting said driveand idler shafts spaced above the surface of the water in said tank forallowing said paddle blades to sweep longitudinally across the watersurface and remove said floating foamed colloidal material.